The present invention generally relates to a rotatable pallet changer. More specifically, the present invention relates to a rotatable pallet changer for use with an automatic machining center. Further, the present invention relates to a rotatable pallet changer and automatic machining center system. In addition, the present invention relates to a method for using the same.
It is, of course, generally known to provide automatic machining centers which employ a bed which is movable in a horizontal plane in two dimensions. Further, it is known to employ an automatic pallet changer employing a workpiece positioned on the pallet and having a draw plate for up and down motion of a pallet resting on the draw plate. Such a receiver is disclosed, for example, in U.S. Pat. No. 5,492,214. Parts being machined in the automatic machining center are fixed to the pallet by an operator.
Such machining centers have a vertically sliding door for closing off an entrance in the machining center enclosure. At the beginning or end of the machining center, the pallet is either moved into or out of the machining center by the automatic pallet changer. When the pallet is outside the enclosure, then it is accessible for a worker to either remove or mount the workpiece being machined.
Further, it is generally known to provide a pallet changer to automatically move first and second pallets into or out of the machining enclosure of the machining center. Such a pallet changer is previously disclosed in U.S. Pat. No. 5,813,514, for example, the disclosure of which is incorporated herein in its entirety. In the '514 patent, first and second pallets are employed such that a worker may be working with one of the pallets while the pallet is outside the machining center while the other pallet is inside the machining enclosure. The pallets can then be automatically exchanged.
Finally, it is generally known to provide an automatic pallet system whereby an automatic pallet changer is provided having first and second tracks provided side-by-side, with each track having a respective pallet associated with it. A chain-like horizontal loop is provided between the two tracks. A single dog is provided on the chain for ultimately engaging with the two pallets. Thus, one pallet is pulled out of the machining center enclosure and, thereafter, the second pallet is brought into the enclosure as the chain continues rotation.
However, these known pallet systems having tracks side-by-side only allow a worker to change the machined part on one track on one side of the pallet changer. If the worker wants to change the pallet on the other track, the worker must move his location to the other side of the pallet changer to do so. This causes a worker to waste time and energy moving from one side of the pallet changer to the other.
A need, therefore, exists for an improved pallet changing apparatus, system and method whereby the pallet changer rotates and a worker needs only to stand on one side of the pallet changer to change the pallet on either track.